Interesting and easy math game

[wendybeth]

Originally Posted by Ghoulish Delight

Well, if X=the first 3 digits of your phone number and Y=the last 4, then your phone number can be represented as 10000X+Y

So, the operations you perform look like this:

(80X+1)*250+2Y-250
___________________
2

Simplifying the numerator, you get 20000X+250+2Y-250.

The +250 and -250 cancel out, leaving you with 20000X+2Y. Divide that by 2 and you get 10000X+Y, which of course is your phone number.

My brain hurts just looking at that.